This application claims priority from Japanese patent application of Ikeda et al, filed Nov. 12, 2001, No.2001-346676, the complete disclosure of which is hereby incorporated into the present application by this reference.
1. Field of the Invention
The present invention relates to a head protecting airbag device including an airbag, which is folded and housed above the upper edge of a window in the interior of a vehicle so that it may be expanded downward to cover the interior side of the window when the airbag admits an inflating gas.
2. Description of the Related Art
Usually, the head protecting airbag device of this kind is desired to expand quickly at a necessary time for protecting a passenger properly with the expanded airbag. Therefore, a head protecting airbag device constructed to expand the airbag quickly is disclosed in Unexamined Published Japanese Patent Application No. 2000-296753.
In this head protecting airbag device, two gas inlet ports are arranged at the upper edge near the middle position in the longitudinal direction of the airbag so as to confront each other in the longitudinal direction. In the construction, moreover, the front and rear ends of an inflator are individually connected to those two gas inlet ports. In other words, the inflating gas, as discharged from the two ends of the inflator, is introduced through two gas inlet ports of the airbag in two directions, i.e., to the front side and to the rear side in the longitudinal direction of the vehicle into the airbag.
However, the head protecting airbag device of the prior art is constructed such that the inflating gas discharged from the two ends of one inflator is guided into the airbag through the two gas inlet ports arranged in the airbag. This makes it necessary to connect the two ends of the inflator and the two gas inlet ports while considering the sealing properties. As a result, the connecting works is complicated to increase the number of steps of and raise the cost for the manufacture.
The present invention has an object to provide a head protecting airbag device which can reduce the number of steps of and lower the cost for the manufacture while retaining the quick completion of expansion of the airbag.
This object of the invention can be achieved by a head protecting airbag device having the following construction:
A head protecting airbag device comprising:
an airbag folded and housed above the upper edge of a window on the interior side of a vehicle and adapted to be inflated downward, when the airbag admits an inflating gas, to cover the interior side of the window,
wherein the airbag includes an airbag body and a flexible current regulating cloth,
wherein the airbag body includes: an inflation shielding portion for shielding the interior side of the window; a gas feed passage portion for guiding the inflating gas discharged from an inflator into the inflation shielding portion; and one gas inlet port constructed to be connected to the inflator,
wherein the inflation shielding portion is inflated to separate an interior side wall portion from an exterior side wall portion by admitting the inflating gas,
wherein the gas feed passage portion is arranged above the upper edge of the inflation shielding portion and in the longitudinal direction of the vehicle,
wherein the gas inlet port is arranged to communicate with the portions in the gas feed passage portion excepting the vicinity of the front end and the vicinity of the rear end and to protrude upward from the gas feed passage portion,
wherein the current regulating cloth includes an inlet side portion arranged in the gas inlet port and connectable with the inflator, and an outlet side portion arranged near the gas inlet port of the gas feed passage portion, and
wherein the outlet side portion includes a first gas outlet hole and a second gas outlet hole capable of releasing the inflating gas discharged from the inflator to the front side and the rear side along the gas feed passage portion.
In the head protecting airbag device of the aforementioned construction, the inflator is connected to one gas inlet port formed in the airbag body. And, the inflating gas discharged from the inflator is guided into the airbag body in the two longitudinal directions, i.e., toward the front and rear of the vehicle, by the current regulating cloth arranged near the gas inlet port. Unlike the prior art, therefore, it is unnecessary to arrange two gas inlet ports in the airbag. Specifically, it is sufficient to arrange one gas inlet port in the airbag and to connect that one gas inlet port to the inflator. This makes it possible to reduce the number of steps of and lower the cost for manufacturing the airbag device.
In the head protecting airbag device of the aforementioned construction, moreover, the gas feed passage portion is arranged in the longitudinal direction of the vehicle. And, the current regulating cloth is provided with the first and second gas outlet holes capable of releasing the inflating gas forward and rearward along the gas feed passage portion. Therefore, the inflating gas released from the first and second gas outlet holes of the current regulating cloth flows into the airbag body forward and rearward of the airbag body along the gas feed passage portion. Specifically, the inflating gas quickly flows to the two longitudinal end sides of the inflation shielding portion arranged on the lower side of the gas feed passage portion. And, whole of the inflation shielding portion can be expanded quickly. As a result, the airbag body can quickly complete its inflation and cover the interior sides of the windows.
Therefore, the head protecting airbag device of the aforementioned construction can reduce the number of construction steps and lower the cost of manufacture by retaining the quick expansion and inflation of the airbag.
In the head protecting airbag device of the aforementioned construction, further, the inflating gas released from the outlet side portion of the current regulating cloth can be guided into the airbag body forward and rearward of the airbag body along the gas feed passage portion. Therefore, the outlet side portion of the current regulating cloth need not be arranged substantially all over the gas feed passage portion in the airbag body, but it is sufficient to arrange the outlet side portion of the current regulating cloth in the gas feed passage portion near the gas inlet port. As a result, the current regulating cloth can be made compact and minimize the volume of the upper side portion at the time when the airbag is folded.
In the head protecting airbag device of the aforementioned construction, moreover, the inflating gas can be branched and released out forward and rearward along the gas feed passage portion by the current regulating cloth itself. In other words, the construction does not mainly change the flow of the inflating gas by the airbag body itself so that the damage to the airbag body by the inflating gas can be suppressed.
Moreover, the head protecting airbag device of the aforementioned construction preferably has a construction,
wherein the outlet side portion is formed into a generally cylindrical shape having its two front and rear ends opened to form the first and second gas outlet holes, and
wherein the outlet side portion is made to have an external diameter size smaller than the internal diameter size of the gas feed passage portion in the airbag body.
With this construction, at the initial stage of inflation of the airbag body, the current regulating cloth is not inflated in such a way that it expands the gas feed passage portion, even if the current regulating cloth is inflated by the inflating gas admitted, so that the damage to the airbag body can be suppressed. This is because the external diameter size of the outlet side portion in the current regulating cloth is made smaller than the internal diameter size of the gas feed passage portion.
Moreover, the head protecting airbag device of the aforementioned construction preferably has a construction, wherein the outlet side portion further includes a third gas outlet hole formed in the lower side between the first gas outlet hole and the second gas outlet hole for injecting the inflating gas downward.
With this construction, the inflating gas discharged from the inflator can be released downward from the third outlet hole formed in the current regulating cloth, into the airbag body. In accordance with the downward inflow of the inflating gas, therefore, the vicinity of the gas inlet port of the airbag body can be quickly inflated downward so that the airbag body can complete its inflation more quickly.
Still moreover, the head protecting airbag device of the aforementioned construction preferably has a construction wherein joint portions are arranged near the lower edges of the first and second gas outlet holes of the current regulating cloth in the airbag body, extend in the longitudinal direction, and are joined to the interior side wall portion and the exterior side wall portion so as to form the lower edge side of the gas feed passage portion.
With this construction, at the initial stage of inflation of the airbag body, the lower edge sides of the first and second gas outlet holes can be supported by the horizontal joint portions when the current regulating cloth admits the inflating gas and releases it from the first and second gas outlet holes into the airbag body. Therefore, it is possible to suppress the downward deviation of the portions of the current regulating cloth near the first and second gas outlet holes when the inflating gas flows out. As a result, it is possible to stabilize the outflow direction of the inflating gas into the airbag body.
Still moreover, the head protecting airbag device of the aforementioned construction preferably has a construction,
wherein the opening faces of the first and second gas outlet holes in the outlet side portion tilt diagonally from the vertical direction when the inflating gas flows out, and
wherein the inflating gas spurting from the first and second gas outlet holes are released in two directions, i.e., downward slanting to the front and to the rear in the longitudinal direction of the airbag body.
With this construction, the inflating gas discharged from the inflator is released from the first and second gas outlet holes of the current regulating cloth in the two directions, i.e., obliquely downward to the front side and to the rear side in the longitudinal direction of the airbag body. Therefore, the flow of the inflating gas to the front side and the rear side in the vehicular longitudinal direction can be retained, even if the outlet side portion of the current regulating cloth is not arranged to go far into the gas feed passage portion. As a result, the current regulating cloth can be made more compact. With this construction of the current regulating cloth, moreover, when the airbag body is folded, the volume of the portion near the gas inlet port can be reduced to allow the airbag to be folded compactly.
Still further, the head protecting airbag device of the aforementioned construction preferably has a construction,
wherein the inflator includes a generally column-shaped body portion, and a generally cylindrical diffuser capable of being mounted on the body portion,
wherein the body portion includes gas discharge ports capable of discharging the inflating gas,
wherein the diffuser is provided in its circumference with an injection port for injecting the inflating gas discharged from the gas discharge ports, and has high shape hold ability than the current regulating cloth,
wherein the diffuser is so assembled together with the body portion as to inject the inflating gas from the injection port, discharged from the gas discharge ports,
wherein the inflator is so inserted, when assembled with the airbag, into the inlet side portion in the current regulating cloth as to support the current regulating cloth, and
wherein the injection port is arranged to inject the inflating gas out of the outlet side portion slanting downward.
With this construction, the inflating gas discharged from the body portion of the inflator can be injected by the diffuser to the side of the outlet side portion of the current regulating cloth. This makes it possible to suppress the damage to the current regulating cloth when the airbag is expanded and inflated. Because, the diffuser has higher shape holdability, in other words, more rigid than the current regulating cloth. Moreover, the inlet side portion in the current regulating cloth can be supported by the inflator. This construction makes it easy to fix the current regulating cloth.
Still moreover, the head protecting airbag device of the aforementioned construction preferably has a construction, wherein the diffuser is provided with two injection ports capable of injecting the inflating gas in two directions, i.e., obliquely downward to the front side and to the rear side in the longitudinal direction of the airbag body on the side of the outlet side portion.
With this construction, the inflating gas, as discharged from the body portion of the inflator, can be injected in the two directions, i.e., obliquely downward to the front side and to the rear side in the longitudinal direction of the airbag body by the diffuser. Therefore, the branching of the inflating gas to both sides in the longitudinal direction of the vehicle need not be made exclusively by the current regulating cloth. As a result, in the head protecting airbag device of the aforementioned construction, the current regulating cloth can be easily manufactured without setting the strength of the current regulating cloth strictly.
Still moreover, the head protecting airbag device of the aforementioned construction preferably has a construction, wherein the gas feed passage portion is arranged substantially all over the entire length, in the longitudinal direction, of the airbag body.
With this construction, the inflating gas which has flowed into the gas feed passage portion can arrive more quickly at the front end side and the rear end side of the airbag body. Therefore, the inflation shielding portion in the airbag body can be inflated more quickly in its entirety.